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The Art and Science of Prediction

As at 1 July 2021 in Australia, there have been around 31,000 positive COVID-19 cases out of a total 21 million tests performed. At such a low incidence of disease, this suggests the test must be close to, or even 100% accurate. Any slight inaccuracy would render many of those cases false positives. If the test accuracy is below 99.85%, ALL of those 31,000 cases will be false positives, merely as a function of the tiny 0.15% inaccuracy of the test!

There is no doubt that uncertainty can cause stress by way of lost hope. It is human nature to keep on hoping against all odds, so when we lose hope, many will turn to anything they believe might recover it.

Some will use meditation or hypnosis to go within to find the answers, while others will search externally, seeking assistance from friends, family, psychologists, counsellors, spiritual leaders, religious teachers and mystics; each with their own special tools of the trade.

A psychologist may use mindfulness, while a mystic's crystal ball may provide the symbolic visions to locate our missing hope. No single process is 100% accurate for all people, all the time, but our emotional state may well determine what we choose to believe to be true.

On the topic of tools of the trade, this pandemic is being measured by a laboratory technique called reverse transcription polymerase chain reaction (RT-PCR ). Because no test is 100% accurate, a margin for error must be incorporated into the results and to this end, positive predictive value (PPV) analysis can be used to assess how many false positives there will be across a tested population. For example, if a test is 99% accurate, there will be 1 person in every 100 who falsely tests positive, and 10 in every 1,000, 100 in every 10,000 and so on.


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